Regenerated cellulose structure and method for preparing same



Patented Nov. 30, 1937 REGENEBATED CELLULOSE STRUCTURE AND METHOD FOR. PREPARING SAME Emil Kline, Buffalo, N. Y., asslgnor, by memo assignments, to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application October 24, 1934 Serial No. 749,823

18 Claims.

This invention relates to a method for improving the dyeing characteristics of regenerated cellulose, and more particularly it relates to a method for improving the affinity of regenerated cellulose structures produced from viscose to basic dyestufis. The invention will be described with specific reference to rayon produced from viscose, it being understood that it is equally applicable to any other product formed from viscose, such as sheets, tubes, ribbons, straw, horsehair, and the like.

It is frequently desired to piece dye fabrics containing threads of both cotton and regenerated cellulose with basic dyestuffs and obtain thereby a color contrast between the cotton and regenerated cellulose threads present therein. For example, brassiere cloth made with cotton and rayon threads is dyed in the piece with a basic dye whereby the rayon threads assume a comparatively deep shade and the cotton threads remain comparatively unaffected.

The basic dyeing of viscose rayon is dependent upon the type and source of cellulose used as raw material. Viscose rayon produced from cotton cellulose or a highly purified wood cellulose does not dye as deeply with basic dyestuffs as rayon made from a less highly purified type of wood pulp. Cotton linters cellulose and the better grades of wood pulp, including high alpha cellulose wood pulps, can therefore not be used as raw materials for viscose rayon manufacture without sacrificing the deep basic dyeing characteristics of the rayon.

Heretofore, in the production of viscose rayon which was to be later subjected to two-tone basic dyeing, that is, dyeing a mixed cotton and rayon fabric with basic dyestuffs, it was found necessary to use a less highly purified type of wood cellulose, or a mixture of celluloses containing a comparatively large proportion of a less highly purified type of wood cellulose, in order to obtain the desired depth of color. This is decidedly disadvantageous in that the rayon made from these less highly purified types of cellulose, aside from deep basic dyeing, is inferior in quality.

The conventional mordants sometimes used in the basic dyeing of cotton, such as tannic acid, alumina, etc., deepen the basic dyeing of rayon as 'well, but, in addition, they produce a drab or muddy color and impart an undesirable scroop to the yarn. Moreover, basic dye mordants cannot be used when it is a question of dyeing a cotton-rayon mixture since obviously the basic dye mordants will increase the depth of dyeing of both the cotton and the rayon and fail to produce the desired two-tone effect.

It has now been found that viscose rayon made from the more highly purified cellulosic materials, when present in a mixed cotton-rayon fabric, can be successfully dyed to the desirable depth of color with basic dyestuffs and also to a considerable extent with naphthol dyestuffs, without affecting the depth of color imparted to the cotton, if certain organic compounds to be 10 described hereinafter are incorporated into the viscose prior to spinning the same into the thread.

It is therefore an object of this invention to produce viscose rayon with improved basic and 15 naphthol dyeing characteristics.

Another object of this invention is to produce viscose rayon having improved basic and naphthol dyeing characteristics from highly purified cellulose.

A further object of this invention consists in the production of cotton-rayon fabrics in which there is a suitable contrast between the basic and naphthol dyeing characteristics of the cotton and rayon, the rayon portion of which is made from a highly purified type of cellulose.

It is a still further object of this invention to provide a method for deepening and varyingthe basic dyeing of rayon, independent of the source and type of cellulose used in its preparationi 1,

Other objects of the invention will *appear hereinafter. v I p The objects of this invention are attained in general by incorporating into the viscose, prior to the spinning of the same, organic sulfur-con- 35 taining compounds having at least fourteen carbon atoms and preferably having at least 18 and in some case 20 or more carbon atoms. These compounds are for the most part organic derivatives of sulfuric acid in the form of water-soluble. 40 salts, for example, the sodium salt of an alkyl sulfuric acid (RSO4Na in which R contains at least fourteen carbon atoms) and obtainable by reacting a normal primary aliphatic alcohol having at least fourteen carbon atoms with a con- 45 centrated sulfuric acid (specific gravity 1.84), fuming sulfuric acid or chloro-sulfonic acid, at a temperature of about 30-50 0., followed by neutralization with sodium hydroxide to form the sodium salt. In place of using sodium hy- 50 droxide to form salts with the alkyl sulfuric acids, similar inorganic salt-forming compounds such as potassium hydroxide, or compounds of organic origin which result in the production of ammonium derivatives of the alkyl sulfuric acids,

particularly quaternary ammonium salts, e. g. piperidine, mono-, diand tri-alkyl amines, cyclohexylamine, monoand di-alkyl cyclohexylamine, alkylolamines, et cetera, may be used.

The term highly purifiedcellulosic materialrefers to cellulosic materials which produce rayon that has a cotton-like dyeing characteristic with basic dyes, and in general consists of material containing 92% or more of alpha cellulose or mixtures of cellulosic materials in. which the 8-8- gregate contains 92% or more of alpha cellulose. As examples of said mixtures might be mentioned equal portions of purified cotton linters (98% alpha collulose) and wood pulp containing 86% alpha cellulose, or 75% wood pulp containing 90% alpha cellulose and 25% cotton linters. Obviously, many other different mixtures of wood pulp and cotton linters, or other cellulosic materials, can be made in which the alpha cellulose content of the aggregate is 92% or more. This term is also intended to include rayon grade, sulfite wood pulps of extreme whiteness and high purity with respect to organic impurities (resins, etc.) even though the alpha content is in the range 86-92%.

As organic derivatives of sulfuric acid, which may be incorporated in the viscose to improve the basic dyeing characteristics of the rayon, the following may be mentioned: 1) the condensation product of a naphthalene sulfonic acid and formaldehyde, preferably in the form of the sodium salt and described in Guenthers U. S. Patent No. 1,696,199, issued December 25, 1928; (2) sodium petroleum sulfonate which may be obtained by neutralizing with caustic soda the sulfonic acids produced by the reaction between sulfuric acid and various petroleum fractions containing hydrocarbons having at least fourteen carbon atoms; (3) polymerized sodium thiophenol; (4)

4c the formaldehyde-bisulfite compound of polymerized sodium thiophenol; (5) sodium abietene sulfonate; (6) the product obtained by acetylating oleyl alcohol with-acetic anhydride, followed by sulfation with strong sulfuric acid (specific gravity 1.84) and neutralization with caustic soda; (7) the sodium salt of the'product obtained by reacting stearyl alcohol at about 30-50 C. with strong sulfuric acid or other sulfonating agent; and (8) the sodium salt of the product produced by reacting a mixture of oleyl, cetyl and stearyl alcohols with strong sulfuric acid (specific gravity 1.84) at a temperature of about 30-50 C. In general, the sodium alkyl sulfates will include those obtained from myristyl, cetyl, stearyl and oleyl alcohols and having the formula RSOsM, in which R contains at least fourteen-carbon atoms add in which M is an alkali metal. The incorporation of methylene 1,1 dinaphthyl 2,2 disodium sulfonate (thecondensation product of a naphthalene sulfonic acid and formaldehyde) into the viscose has been found to be particularly effective in improving the basic dyeing characteristics of rayon produced therefective, but they are not all equally effective, nor

do they all give rayon that dyes to exactly the same shade. In dyeing with Rhodamine B (Schultz Color Index No. 864; 1931' edition) for instance, the use of some of these compounds results in yellowish-pink or orange shades, whereas with others, bluish-pink, or purple shades are secured. The depth of shade, furthermore, varies with the concentration used in the viscose.

In the following tablethe compounds which have been found effective are listed in approximate order of their effectiveness, together with the shade produced when the material is later dyed with "Rhodamine B":

Quality of Compounds M Methylene 1,1 dimphthyl 2,2 disodium sulfonate. Sodium petroleum aulfenate Sodium sullen Polymerized sodium thiophenol the oduct obtained by the condensation of p eno and sulfur in a sodium hydroxide medium) Formaldehyde blsulflte compound obtained by rcactin polymerized sodium thiophenol with formal ehyde bisulilte The sodium salt of the product obtained by acetylating oleyl alcohol followed by treatment with concentrated sulfuric acid Sodium salts of a mixture of cetyl and stearyl suliuric acid The sodium salt of the product obtained by reacting a mixture of oleyl, cetyl and stearyl alcohols with concentrated sulfuric acid Bluish cast. Yellow cast. Blulsh cast.

Bluish cast.

Blulsh cast.

Yellow cast.

Yellow cast.

Yellow cast.

' Although the dyeing with naphthol dyestuffs is not effected to the same extent as with basic dyestuffs, some of the above listed materials materially increase the depth of dyeing with naphthol dyestuffs and in the following list, the materials are enumerated in the order of their efiectiveness:

1. Sodium petroleum sulfonate.

2. The sodium salt of the reaction product obtained by treating oleyl acetate with concentrated sulfuric acid.

3. Sodium abietene sulfonate.

4. Methylene 1,1 dinaphthyl 2,2' disodium sulfonate.

As mentioned above, the depth of shade produced is dependent upon the concentration of the substance used. The preferred range of concentration of the addition agent in the viscose is from 0.002-0.20%. These concentrations are of the 100% material and are percentages by weight based on the viscose solution containing approximately 7% cellulose. Rayon spun from viscose made with cotton linters or other cellulose materials containing a high percentage of alpha cellulose and containing any one of these addition agents in suitable concentration will dye as deeply as, or even more deeply than similar rayon made entirely from wood pulp of less degree of purity, whereas normally viscose rayon made from cotton linters or other cellulose materials, having a high percentage of alpha cellulose and high purity, dyes very poorly and very lightly with basic dyestuffs.

The theory or underlying reason for the improvement in basic dyeing by the addition of these substances to viscose has not been definitely established. It is believed, however, that these substances, although very soluble in water and alkaline solutions and probably even for the most part soluble in the coagulating bath, are

unusually strongly adsorbed by cellulose, and particularly by gel regenerated cellulose. The adsorption probably occurs during the spinning operation. In fact, it may be a case of adsorption by the coagulated, but unregenerated thread. In any case, the adsorption appears to be very great and the addition agent is fixed in such a way that it is not removed during the spinning or subsequent purification operations. It is in this respect that the materials disclosed differ from ordinary basic dye mordants and this invention must not be confused with the well known art of the use of mordants in the basic dyeing operation. Such well known mordants as tannic acid and alumina, which are very effective in accelerating and deepening the dyeing with basic dyestuffs in the ordinary dye bath, are not effective in this process, namely when they are added to the viscose prior to spinning of the same. Under the latter conditions, these mordants do not influence the basic dyeing of the rayon spun therefrom.

As illustrative examples of methods of improving the' basic dyeing characteristics of regenerated cellulose materials are given the'following:

Example L-One pound of an aqueous solution of the sodium salt of dinaphthyl methane-disulfonic acid (the product formed by condensing naphthalene beta-sulfonic acid with formaldehyde) is prepared containing 30% of the substance. This solution is incorporated in 5,000 pounds of viscose prepared from cotton linters cellulose (about 98% alpha cellulose) containing 7% cellulose by adding it to the caustic and water prior to the addition of the cellulose 'xanthate. The xanthate is then added and mixing, filtration, ripening and spinning of the resulting viscose is carried on in the usual manner. The yarn obtained is processed and purified as usual. Upon dyeing with basic dyestufis, such as Rhodamine B, this yarn will dye deeply and uniformly and will give a pleasing two-tone contrast in a piece-dyed rayon-cotton fabric.

Example II.-Viscose containing 7% cellulose is prepared in the usual way from a 50-50 mixture of cotton linters cellulose (98% alpha) and wood pulp cellulose (88% alpha). Before mixing is complete and while the viscose is stillin the solution mixer, suflicient sodium petroleum sul fonate is added to give 0.05%, by weight, of this material in the viscose. pleted and the viscose is filtered, ripened and spun in the usual, well known manner. The yarn is likewise processed in the conventional manner. When dyed with direct dyestuffs, it will be found that thisrayon acts similar to rayon produced from untreated viscose made from the same celluiosic material in the depth and quality of shade produced. However, upon dyeing with basic dyestuffs, such as Rhodamine B, the shade produced is considerably deeper-than that obtained with such rayon produced from untreated viscose or the same depth of shade may be produced using considerably less dyestufi.

Example III.A solution of sodium abietene sulfonate is added to 7% cellulose viscose in sufficient quantity to give a concentration of 0.1% of sodium abietene sulfonate in the finished viscose. The viscose is processed and spun and the rayon yarn is purified in the normal manner. Under the same conditions of dyeing, this yarn will dye much more readily and to a deeper shade with Rhodamine B than yarn produced from similar viscose without the addition of the sodium abietene sulfonate. A greater two-tone contrast in piece dyed rayon-cotton fabrics will be obtained in this manner with no change in the dyeing characteristics with other types of dyestuffs.

Among the advantages of my invention is the production of a highly satisfactory viscose rayon Mixing is then com which, in addition, has a greater capacity for basic dyeing than rayon made from untreated viscose. Furthermore, mixed cotton-rayon fab rics can be produced in which the rayon content may be made from a highly purified type of celluiosic material, which rayon content can be given any desired depth of color with basic dyes in contrast to the cotton content. so as to obtain a fabric of any desirable two-tone effect.

' modifications may be made in the above description without departing from the nature and spirit thereof, it is to be understood that the invention is not to be limited thereto except as set forth in the appended claims.

I claim: Y

1. The process which comprises incorporating into viscose made from cellulose having an alpha cellulose content of atleast 92% a compound soluble therein, said compound having at least 14 carbon atoms and being taken from the class consisting of an alkali metal salt of naphthalene sulfonic acid condensed with formaldehyde, alkali metal petroleum sulfonate, alkali metal abietene sulfonate, polymerized alkali meta thiophenol and its formaldehyde-bisulfite condensation product, alkali metal stearyl sulfate, alkali metal oleyl sulfate, alkali metal cetyl sulfate, alkali metal myristyl sulfate, and an alkali metal salt of the product obtained by sulfating a normal primary acetylated aliphatic alcohol, spinning the viscose into threads, fabricating the thread into a fabric with a textile material having a lower affinity than said thread for dyestuffs of the class consisting of basic and naphthol dyestuffs, and dyeing said fabric with a dyestuff taken from the class consisting of basic and naphthol dyestuffs.

2. The process of claim 1 characterized in that said textile material is cotton and said dyestufi is a basic dyestuff.

3. The process which comprises incorporating into viscose made from cellulose having an alpha cellulose content of at least 92% a compound soluble therein, said compound being an alkali metal salt of an organic derivative of sulfuric acid having at least 14 carbon atoms, spinning the viscose into thread, fabricating the thread into a fabric with a textile material having a lower afi'inity than -said thread for dyestuffs taken from the class consisting of basic and naphthol dyestufi's, and dyeing said fabric with a dyestufi taken from the class consisting of basic and naphthol dyestuffs.

4. The process of claim 3 characterized in that said textile material is cotton and said dyestuif is a basic dyestuif.

5. The process of claim 3 characterized in that said organic derivative of sulfuric acid is a sulfonic acid having at least 14 carbon atoms.

6. The process of claim 3 characterized in that said salt of an organic derivative of sulfuric acid is a sodium salt of a sulfonic acid of a carbocyclic hydrocarbon having at least 20 carbon atoms.

7. The process of claim 3 characterized in that said organic derivative of sulfuric acid is an alkyl sulfate having at least 14 carbon atoms.

8. The process of claim 3 characterized in that said salt of an organic derivative of sulfuric acid is the disodium salt of dinaphthyl methane disulfonic acid.

9. The process of claim 3 characterized in that said salt of an organic derivative of sulfuric acid is the sodium salt of dinaphthyl methane disulfonic acid and said textile material is cotton and said dyestufl is a basic dyestufi.

10. A mixed fabric comprising regenerated cel- I lulose rayon made from cellulose having an alpha cellulose content of at least 92% and having incorporated therein a water soluble alkali metal salt of an organic derivative of sulfuric acid having at least 14 carbon atoms, and a textile material having a lower aflinity than said regenerated cellulose for dyestuffs taken from the class consisting ofbasic and naphthol dyestufls, and a dyestuff taken from the class consisting of basic and naphthol dyestufis.

11. The article of claim 10 characterized in that said textile material is cotton and said dyestuff is a basic dyestufi.

12. The article of claim 10 characterized in that said organic derivative of sulfuric acid is a sulfonic acid having at least 14 carbon atoms.

13. The article of claim 10 characterized in that said salt of an organic derivative of sulfuric acid is a sodium salt of a sulfonic acid of a carbocyclic hydrocarbon having at least 20 carbon atoms.

14. T'he article of claim 10 characterized in that said organic derivative of sulfuric acid is an alkyl sulfate having at least 14 carbon atoms.

15. The article of claim 10 characterized in that said salt of an organic derivative of sulfuric acid is the disodium salt of dinaphthyl methane disulfonic acid.

16. The article of claim 10 characterized in that said salt of an organic derivative of sulfuric acid is the disodium salt of dinaphthyl methane disulfonic acid and'said textile material is cotton and said dyestuii' is a basic dyestuif.

17. A mixed fabric comprising regenerated cellulose rayon made from cellulose having an alpha cellulose content of at least 92% and having incorporated therein a water soluble compound, said compound having at least 14 carbon atoms and being taken from the class consisting of an alkali metal salt of naphthalene sulfonic acid condensed with formaldehyde, alkali metal petroleum sulfonate, alkali metal abietene sulfonate, polymerized alkali metal thiophenol and its formaldehyde-bisulflte condensation product, alkali metal stearyl sulfate, alkali metal oleyl sulfate, alkali metal cetyl sulfate, alkali metal myristyl sulfate, and an alkali metal salt of the product obtained by sulfating a normal primary acetylated aliphatic alcohol, in combination with a textile material having a lower afllnity than said rayon for dyestufls taken from the class consisting of basic and naphthol dyestuffs, and a dyestufl taken from the class consisting of basic and naphthol dyestuffs.

18. The article of claim 17 characterized in that said textile material is cotton and said dyestufl is a basic dyestufl.

. EMIL KLINE. 

